Stenothemus laticornis Y. Yang & H. Liu, 2021

Yang, Yuxia, Ge, Shujuan, Yang, Xingke & Liu, Haoyu, 2021, Taxonomic revision of the species of Stenothemus from Southwest China (Coleoptera, Cantharidae), with the descriptions of five new species, European Journal of Taxonomy 757 (1), pp. 1-36 : 29-32

Stenothemus laticornis Y. Yang & H. Liu sp. nov.

urn:lsid:zoobank.org:act:C54780B5-A2AF-4FC8-B8A7-6AE3D067D8DF

Figs 7F , 9E , 11A‒C , 12D

Differential diagnosis

It appears to resemble S. hajeki Švihla, 2011 (from China: N Yunnan), but differs in the following characters: apices of femora yellow, while uniformly black in S. hajeki ; antennae almost reaching apices of elytra, while clearly exceeding them in S. hajeki ( Švihla 2011: fig. 19); aedeagus: ventral processes of parameres strongly approaching each other, distinctly thickened apically and bent dorsally, while in S. hajeki ( Švihla 2011: figs 93‒95) the slightly approach each other, and are slightly thickened and bent ventrally.

Etymology

The specific name is derived from the Latin ‘ latus ’ (‘wide’) and ‘ cornus ’ (‘horn’), referring to its flattened and widened antennae.

Material examined

Holotype

CHINA • ♂; Chongqing, Chengkou, Zuolan, Qixin ; 32.180º N, 108.485º E; 1070 m a.s.l.; 9 Jul. 2017; Y. Zhou leg.; MHBU HBU(E) 410045 .

Paratypes

CHINA ‒ Chongqing • 1 ♂; Chengkou, Dong’an, Shengjiaping ; 31.791º N, 109.241º E; 1819 m a.s.l.; 16 Jun. 2017; Y. Zhou leg.; MHBU HBU(E) 410046 • 1 ♀; Chengkou, Xianyi, Mingyue ; 1184 m a.s.l.; 24 Jun. 2017; Y. Zhou leg.; MHBU HBU(E) 410047 .

Description

Body length (both sexes): 7.2‒8.0 mm (7.2 mm in holotype); width: 1.5‒1.8 mm (1.7 mm in holotype).

Male ( Fig. 9E )

COLORATION. Body black, clypeus, mouthparts and bases of femora light yellow, pronotum testaceous, lightened at anterior angles. Body densely covered with short, semi-recumbent pale pubescence.

HEAD. Subquadrate, surface densely and finely punctate, each side with a smooth and rectangular impression behind antennal socket; eyes strongly protruding, head width across eyes 1.5 times wider than pronotum; terminal maxillary palpomeres long-triangular, widest at basal ⅔; antennae filiform, almost reaching apices of elytra, antennomeres II about 1.1 times as long as wide at apices, III about 2.9 times longer than II, IV‒XI flattened and each with a small and smooth oval impression in middle of outer edge, IV widest, V to XI gradually narrowing towards apex, XI slightly longer than X, pointed at apex.

PRONOTUM. Subquadrate, about 1.1 times as long as wide, anterior margin arcuate, anterior angles obtuse, subrounded, lateral margins slightly sinuate, posterior margin slightly sinuate and narrowly bordered, posterior angles sub-rectangular, disc strongly convex on posterolateral parts, surface finely and densely punctate.

ELYTRA. Nearly parallel-sided, about 3.6 times as long as humeral width, 4.6 times as long as than pronotum, surface finely and densely punctate, with hardly visible longitudinal costae.

AEDEAGUS ( Fig. 11A‒C ). Moderately swollen laterally at basal part, strongly reduced in diameter apically; basal piece nearly as long as dorsal plate of each paramere, with a large, bifurcate conjoined middle nodule at base of ventral side; ventral processes of parameres strongly approaching each other, short and distinctly thickened apically, bent dorsally in lateral view; dorsal plates slightly longer than ventral processes, strongly narrowed near base, approaching each other, apex acute; apical parts of laterophyses depressed and separated from each other, apex wide-triangular and weakly exceeding middle emargination between dorsal plates.

Female

Similar to male, but body stouter than male, eyes small, less protruding, head width across eyes 1.4 times wider than pronotum, antennae shorter and roughly extending to elytral mid-length, IV‒XI without impressions; elytra about 3.2 times as long as humeral width.

ABDOMINAL STERNITE VIII ( Fig. 7F ). Moderately narrowed posteriorly, lateroapical angles widely rounded, posterior margin widely and roundly emarginate in middle and feebly sinuate on both sides, behind the notch with a membrane which is sclerotized and triangularly bilobed at apex.

INTERNAL ORGAN OF REPRODUCTIVE SYSTEM ( Fig. 12D ). Vagina stout, with median oviduct situated at ventroapical part, vagina abruptly narrowed in apical part and extended into a short duct which diverticulum and spermathecal duct are arising from; diverticulum moderately long, about 0.58 times adult body length, evenly thinned apically, slender tube-shaped and spiral; spermathecal duct moderately long but much shorter than diverticulum; spermatheca slender tube-shaped and spiral, obviously thinner than spermathecal duct and nearly as long as diverticulum, with basal part extended into a short tube, at opening of accessory gland. Accessory gland thin in basal part and the remainder moderately thin, obviously shorter than spermatheca.

Distribution

China (Chongqing).

Figures

Fig. 7. Abdominal sternite VIII of female, ventral view. A. Stenothemus minutissimus (Pic, 1933) comb. nov. (IZAS, Sichuan). B. S. tryznai Švihla, 2004 (IZAS, Sichuan). C. S. singularicollis (Pic, 1933) comb. nov. (MHBU, Shaanxi). D. S. gracilis Y. Yang & X. Yang sp. nov., paratype (IZAS IOZ(E) 225787). E. S. flavicollis Y. Yang & S. Ge sp. nov., paratype (MHBU HBU(E) 410039). F. S. laticornis Y. Yang & H. Liu sp. nov., paratype (MHBU HBU(E) 410047). Scale bars = 1.0 mm.

Fig. 9. Habitus, dorsal view. A. Stenothemus gracilis Y. Yang & X. Yang sp. nov., holotype, ♂ (MHBU HBU(E) 410022).B. S. chongqingensisY.Yang & H. Liusp. nov., holotype, ♂ (MHBU HBU(E) 410028). C. S. flavicollis Y. Yang & S. Ge sp. nov., holotype, ♂ (MHBU HBU(E) 410029). D. S. jindraimimus Y. Yang & X. Yang sp. nov., holotype, ♂ (IZAS IOZ(E) 1389239). E. S. laticornis Y. Yang & H. Liu sp. nov., holotype, ♂ (MHBU HBU(E) 410045). Scale bars = 1.0 mm.

Fig. 11. Aedeagus of Stenothemus laticornis Y. Yang & H. Liu sp. nov., holotype (MHBU HBU(E) 410045). A. Ventral view. B. Dorsal view. C. Lateral view. Scale bar = 0.5 mm.

Fig. 12. Female reproductive system, ventral view. A. Stenothemus singularicollis (Pic, 1933) comb. nov. (MHBU, Shaanxi). B. S. gracilis Y. Yang & X. Yang sp. nov., paratype (IZAS IOZ(E) 225787). C. S. flavicollis Y. Yang & S. Ge sp. nov., paratype (MHBU HBU(E) 410039). D. S. laticornis Y. Yang & H. Liu sp. nov., paratype (MHBU HBU(E) 410047). Abbreviations: see Material and methods. Scale bars = 0.5 mm.